How to get warranty satisfaction from Kenmore/ Sears?

My mother bought a new Kenmore frig from Sears Clearview on 6/23/18. In mid April the frig part stopped cooling, but the freezer worked fine. She called the repair department and they sent out a technician and he steam defrosted the frozen coils and it worked fine. About a week later same thing happened and he came out again and defrosted again and said he had to order parts to fix it permanently. Since then it freezes over about once a week and it has to be defrosted. The technician claims the parts are not availible to repair.

My mother called again last Wednesday and they said that he would come out Thursday and he was a no show. She called again Friday and Sears said he would be out today . Another no show.

Sears referred my mother to Sears Customer Solutions. They are the complaint department. But when you call them, you are put on hold. Today she called them after the no show and she was out on hold for 50 minutes. She finally hung up.

Does anyone know a way to get Sears/ Kenmore to respond and fix the frig?